HTP, the active control intervention, consists of weekly sessions alternating between (a) coaching sessions covering one of five domains of child development (Motor, Cognitive, Language, Play, and Social-Emotional and (b) observation sessions that will include a review of the prior coaching session and an observation and discussion of the caregiver-child interaction.

The Strengths and Difficulties Questionnaire (SDQ) is a brief behavioural screening questionnaire. 25 items are asked on a 3-point scale from not-true to certainly true. Followed by 5 items assessing difficulties with emotions, concentration, behavior or being able to get along with people.

The Opioid Craving Scale is a modification of the Cocaine Craving Scale (Weiss et al., 1995, 1997, 2003) used to measure opioid craving. The scale consists of three items rated on a visual analogue scale from 0-10

This measure is a 9-item self-report of income, occupation and financial strain.

Measures social support, yielding scores for:

• Perceived number of social supports
• Satisfaction with social support that is available Questionnaire consists of 27 items with 2-part responses (listing the people they can turn to and rely upon and how satisfied they are with the social supports).

Each item is scored based on the number of support persons listed, and the satisfaction scale scored on a scale of 1 to 6 (1 = very satisfied and 6 = very dissatisfied). The overall number and satisfaction scores are summed and divided by 27.

The Family Environment Scale (FES) is a self-report 90-item instrument developed to assess the social climates of families focusing on the measurement and description of interpersonal relationships among family members on the directions of personal growth and the basic organizational structure of the family.

The Cohesion subscale is a 9-item scale intended to measue the degree of commitment and support that family members provide each other. Respondents rate statements on a scale from mostly true to mostly false.

The MacArthur Communicative Development Inventories (MCDI) are parent- report instruments for assessing communicative skills in infants and toddlers.

The infant form (Level I), designed for children between 8 and 18 months, contains an 89-word vocabulary checklist with separate columns for comprehension and production. There are two equivalent forms of the toddler form (Level II, Forms A and B), both designed for children between 16 and 30 months. Each form contains 100 vocabulary items.

Use appropriate norming tables for girls and boys to furnish raw score values for every 5th percentile level from the 5th to the 99th rank.

Inhibitory control will be assessed by the Stop Signal Task (SST) during an MRI scan. The task speed adjusts based on performance and a single response time score will be outputted for each participant. The key neural measure is the degree of blood oxygenation-level dependent (BOLD) signal during stop trials relative to go trials (i.e., the "stop > go" contrast over the entire trial period).

The PSET involves visual presentation of single words or short phrases in the parenting domain (e.g., kind, supportive, enforces rules) seen under two different instruction conditions. The identity condition will ask participants to indicate via a button press whether the word or phrase describes them as a parent (left index finger = yes, right index finger = no). The control condition will ask participants to indicate via a button press whether the word or phrase is a quality that can change for a parent (yes/no). Scores are percent endorsement of developmentally-supportive (DS) and developmentally-unsupportive (DU) items in each condition. The key neural contrasts are neural activation during the presentation of (a) identity > control trials and (b) identity-yes > identity-no trials.

Conversational turns is a simple coding scheme designed to record timing, quantity, and length of caregiver and child utterances.

The Iowa family interaction rating scales were used to assess parent's warmth and hostility towards their partner, their perceived warmth and hostility received from their partner, and warmth and hostility towards their child. The questionnaire is divided into 3 parts; the first 10 questions ask how you have behaved towards your partner, the next 10 ask how your partner has behaved towards you, and the final 10 questions ask how you have behaved towards your child.

There are 2 scales for each part of the questionnaire, warmth (6 items) and hostility (4 items). For both scales each item has a possible 7 responses. Each scale reverse scored and then summed by adding each item score, giving a possible range of 0-42 for the warmth scale and 0-28 for the hostility scale. Higher scores indicate higher levels of warmth/hostility respectively.

The ACE is a 10-item measure of childhood adversity and is often used as a predicter of poorer outcomes later in life. The higher the score out of 10, the more likely for poor outcomes.

Sum the scores of all responses 1-10 for total ACE score. Reverse code the emotional neglect question, question 10, which counts as an ACE if either sub-question is answered "No." The developers suggest not including the supplemental questions in the Total ACE score. They recommend remaining true to the original ACE 10 categories so we can compare data across sites. If desired, you can sum the scores on the supplementary questions, and create a supplementary grand total to examine separately.

TotalACES=total ACE score TotalSupp=sum of supplemental questions TotalAll=Sum of ACE score and supplemental question score

This measure consists of 23 questions that assess 13 psychiatric domains, including depression, anger, mania, anxiety, somatic symptoms, suicidal ideation, psychosis, sleep problems, memory, repetitive thoughts and behaviors, dissociation, personality functioning, and substance use. Each item inquires about how much (or how often) the individual has been bothered by the specific symptom during the past 2 weeks.

Intervention Fidelity is assessed by the number of required items completed from a checklist of required actions for the given intervention.

Intervention Dosage is assessed by the number of completed sessions for each intervention.

Total FIND Sessions Complete = Count of sessions complete (0-10) Total HTP Sessions Complete = Count of sessions complete (0-10)

The QUIC, a reliable and valid self-report assessment of exposure to unpredictability in the social, emotional, and physical domains during early life, is a brief, comprehensive, and promising instrument for predicting risk for mental illness. The QUIC consists of an overall score and five separate subscale scores. Higher scores indicate more exposure to unpredictability in childhood. To obtain the overall score or subscale scores, reverse score select items (indicated by an R after the item number) and then calculate the sum of the items in each scale: Parental monitoring and involvement = 1R + 3R + 4R + 5R + 6R + 7R + 9R + 10R + 14R Parental predictability = 2 + 8R + 11 + 12 + 15R + 16 + 17R + 31 + 32 + 33 + 34 + 35 Parental environment = 18 + 19 + 21 + 22 + 28R + 29 + 30 Physical environment = 13 + 20 + 26 + 27 + 36R + 37 + 38 Safety and security = 23 + 24 + 25 Overall = Sum of all subscales.

Questionnaire developed from PhenX and iOpen to assess substance use and treatment history.